LNER passengers are only allowed to board trains if they hold a reservation as well as a ticket, with the company producing a video explaining its new rules.

Passengers are being asked to sit in a window seat, with one person per row of four seats, and two empty rows between each passenger.

People from the same household will be allowed to sit together but must maintain "a safe distance" from other people.

The increase in services comes as the government urges those returning to work to not use public transport if they can.

Unions have complained this is sending mixed messages to millions of workers, with many still wondering whether it is safe to return to their workplace.

Image:Leeds station during rush hour on Monday morning

The move comes at the start of the first full working week since Boris Johnson set out his plan for easing the coronaviruslockdown in England, urging those employees unable to work from home to return to their places of employment.

Meanwhile, many recycling centres in England will reopen, discount chain Poundland is to reopen 36 stores, and early-morning swimmers can enter the water at Britain's oldest swimming club at the Serpentine in Hyde Park, west London.

The Rail Delivery Group said train services will be increased from around 50% of the standard timetable to 70%.

However, in order to maintain social distancing, their capacity will be reduced to as little as 10% of normal levels, and passengers are being urged to avoid non-essential travel.

Robert Nisbet, of the Rail Delivery Group, said operators faced challenges from increasing travel capacity.

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He told Sky News: "We are introducing a number of measures such as enhanced cleaning of trains and maintaining social distancing to make sure our passengers are as safe as possible.

"The advice is only take a train if it's absolutely necessary but consider other means of transport such as walking or cycling."

More British Transport Police officers will be deployed to London stations in a bid to control crowds.

Passengers should wear face masks and continue keeping a two-metre distance from other people where possible.

The government is urging transport operators to rearrange, remove or limit seating "to try and ensure social distancing is observed", which may include blocking off seats in close proximity to others and removing face-to-face seating.

It is also demanding the compulsory wearing of face masks by passengers, which should be provided for free at stations and be able to be disposed of safely.

A Department for Transport spokesman said the message remained that people should only go to work if they cannot work from home.

He said they should avoid public transport if possible and maintain social distancing if they have no other choice.

Culture Secretary Oliver Dowden told Kay Burley@Breakfast: "It remains the case that people should work from home if they possibly can. Of course if they can't, they should look to return to work.

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"That will reduce the numbers of people on public transport significantly. We're also saying that people should look to alternative means of transport if they can.

"If people are still using public transport, we have introduced rules about how public transport should be conducted in a way that makes it as safe as possible."

He added that there "may be some queueing at peak times" in order to ensure social distancing could be adhered to.

Asked if he would get on a train - even if social distancing could not be observed - Mr Dowden replied: "Yes I would get on a train in that situation. But of course we are taking measures to ensure that is not the case."